The principal objective of the proposed research is to identify and characterize some critical cellular mechanisms involved in the formation and maintenance of retinotectal synapses in the amphibian and teleost tectum, using a combination of physiological and biochemical techniques. The retinotectal system provides a favorable model for the study of the molecular mechanism regulating synatogenesis, and these mechanisms are of fundamental importance in the normal and pathological functioning of the nervous system. There are two major goals. The first is to investigate the dynamics of transmitter receptor proteins during optic nerve regeneration. This will be pursued 1) physiologically, in vivo and in tissue slice preparations, in which the biochemical environment can be controlled and intracellular and iontophoretic measurements made under direct visual control; and 2) biochemically, by measuring ACh receptor protein turnover times and changes in receptor properties that might correlate with changes in innervation. The second goal is to develop improved methods to separate specific components involved in synaptogenesis. We have developed two techniques which show considerable population of synaptosomes (i.e., related to optic nerve terminals). The second technique is a quantitative two-dimensional gel electrophoresis method for separating cellular proteins. Using this technique we hope to identify and characterize the dynamics of proteins involved in retinotectal and synaptogenesis.